Non-invasive destruction of kidney stones

ABSTRACT

Apparatus for the non-invasive disintegration of kidney stones and the like. An ellipsoidal reflector open at one end is positionable against the body, and may have a diaphragm across the opened end to prevent leakage of water contained in the reflector. A spark gap is located at the first focal point of the ellipsoid, and sonic aiming means is physically interconnected with the ellipsoid for aiming the ellipsoid at the kidney stone or the like to locate the kidney stone at the second focal point of the ellipsoid. A series of sparks discharged across the spark gap generates a succession of shock waves that travel through water in the reflector, and through the body to impinge on the kidney stone or the like and thereby to disintegrate the same.

This is a divisional of co-pending application Ser. No. 666,770 filed onOct. 31, 1984 now U.S. Pat. No. 4,620,545.

BACKGROUND OF THE INVENTION

Kidney stones, and also naturally occuring stones in the bladder and theureter can be exquisitely painful, and often require surgical relief.Excision or destruction of stones in the bladder and sometimes in theureter can be relatively easily accomplished but removal of stones fromthe kidney is a major procedure.

Removal of stones from the kidney is a very serious and traumaticsurgical procedure. A large incision is made in the body. The kidney isessentially removed from the body and cut open. The stone or stones arethen removed, whereupon the kidney is sutured and returned to the body,with the body then being sutured.

Chemotherapy is available as a non-invasive therapy for uric acidstones. In this therapy the urine is alkalized. The existing stone thusis dissolved over a substantial period of time, and in most cases thepatient can be cured before his condition becomes acute. However, thepatient's condition is often already acute when the stone is discovered,and immediate surgery is imperative. Attempts at chemical dissolution ofother types of stones have not been successful.

There are procedures for removing stones from the bladder which do notrequire cutting of the body. They are, however, invasive procedures inthat the necessary devices are inserted through the urethra. In one ofthese procedures an electrohydraulic impulse is provided. A high energycapacitor is discharged by means of a coaxial electrode within thebladder, whereby a spark jumps between two poles of said electrode,establishing a hydrodynamic wave which destroys the concretion uponcontact. The electrode thus must be in close proximity to the stone anda cystoscope having an optical telescope is utilized to visualize thespark generating electrodes.

As an alternative ultrasonic waves on the order of 27 KHz. are used todisintegrate bladder stones. An optical device and an ultrasoundconverter are carried by a hollow steel probe which is inserted throughthe urethra. High frequency electrical energy is transformed intomechanical energy by an ultrasound converter and carried by the hollowsteel probe which must be in contact with the bladder stone.

With both electrohydraulic impulses and ultrasonic disintegration ofbladder stones it has been necessary for the energy source to be veryclose to or to effect physical contact with the stone. Such proceduresare transuretheral and are routine for bladder stones. Ureteral stonesand kidney stones recently have been fragmented by such techniquespercutaneously. Such procedures are invasive, but do not involve majorcutting of the body.

The percutaneous approach to ureteral and kidney stones has avoided themassive surgery outlined heretofore. A needle is inserted through theskin to the renal pelvis, the collecting area of the kidney. The needleis hollow and a guide wire is inserted through the needle into thekidney. The needle is then removed, and successively larger tubes arerun in over the guide wire, leading up finally to a tube 8 mm indiameter. Viewing and stone cracking apparatus then are inserted throughthis tube to crack or disintegrate the stone. The approach is stillinvasive, and traumatic to the patient.

One approach has been made on an experimental basis of non-invasivebreaking-up or disintegration of kidney stones in the body. Suchnon-invasive disintegration of kidney stones is disclosed in U.S.Patents to Hoff et al U.S. Pat. No. 3,942,531 and Hausler U.S. Pat. No.4,311,147. The first of these patents is exemplified in a machinecommercially available in the Federal Republic of Germany from DornierSystem GmbH. A few of the Dornier machines are now in the United Stateson an experimental basis. Such machines are quite large since theyrequire the patient to be immersed in a tub of water in a crouched,face-up position. Two dimensional X-ray procedures are utilized todetermine the position of the stone by moving the patient. The machineincludes an underwater spark gap shock wave generator which lies outsideof the patient's body and at the first focal point of an ellipsoid. Thepatient is moved around in the water bath by servo mechanisms utilizingthe two dimensional X-ray technique until the kidney stone is positionedat the second focal point of the ellipsoid. Since X-rays are used onlyradio opaque stones can be located. The shock wave is then generated,and passes through the water bath and through the patient's body toconvey the energy to the kidney stone. The Dornier machine requires a 40square meter room 3 meters in height. The machine base is six meters byone meter. The present cost of the machine, which may be expected torise with inflation, is two million dollars, plus 10% of the price ofthe machine each year for a service contract. The service contractincludes the cost of a technician who must be on hand at all times whenthe machine is in operation. It is contra-indicated if the ureter isblocked, since the material must pass out through the ureter. It is alsounsuccessful with radio transparent or translucent stones, since theycannot be located by X-ray techniques. It must be emphasized thatprecise aiming of an external shock wave is necessary since energyfocused into an air or gas pocket in the body can cause damage tointerface tissue.

OBJECTS AND SUMMARY OF THE PRESENT INVENTION

It is an object of the present invention to provide an external shockwave kidney stone disintegrator which is portable, operable by oneperson, and which does not require the patient's body to be immersed ina water bath.

Furthermore, it is an object of the present invention to provide anapparatus and method for external application of a hydraulic shock waveto a patient's body with the shock wave focused on the kidney stone orthe like, which external aiming means is unitized with the shock wavegenerating apparatus to permit precise external aiming of the shock waveby a relatively simple procedure.

It is yet another object of the present invention to provide a kidneystone disintegrator as set forth in the preceding objects wherein asonic aiming system is utilized which readily locates kidney stoneswhich are transparent or translucent to X-rays.

In achieving the foregoing and other objects we provide an ellipsoidalreflector mechanism which is positioned against the surface of the humanbody. A waterproof diaphragm may be provided across the open end of thereflector to retain water in the reflector. The reflector has a sparkgap positioned at the first focal point. The reflector also includes anultrasonic or sonar transmitter and receiver which allows precisepositioning of the reflector against the body so that the kidney stonewill be at the second focal point of the ellipsoid. A succession ofsparks is generated, causing a succession of hydraulic shock waves whichpass through the water in the reflector and through the human body tothe kidney stone. The energy involved is quite substantial. Thissuccession of shocks breaks up the kidney stone, which is then excretedthrough the ureter, the bladder, and the urethra.

THE DRAWINGS

The present invention will be best understood from the followingdescription when taken in connection with the accompanying drawingswherein:

FIG. 1 is a somewhat schematic view, partially in cross-section showingan exemplification of the present invention in combination with thehuman body;

FIG. 2 illustrates the wave shape of the shock wave;

FIG. 3 is a view similar to a portion of FIG. 1 showing further detailson the aiming system;

FIG. 4 is a view generally similar to FIG. 3 on a somewhat reduced scaleshowing a modification of the aiming system;

FIG. 5 is a view similar to FIG. 4 showing the parts in a differentposition;

FIG. 6 is a view generally similar to FIG. 4 and showing a furthermodification of the aiming system;

FIG. 7 is a view similar to FIG. 6 showing the parts in a differentposition of operation;

FIG. 8 is a view of a modification of the CRT display utilizing imagingrather than crossed lines;

FIG. 9 is a view similar to FIG. 8 showing a different aiming condition;and

FIG. 10 is a view similar to FIGS. 8 and 9 showing yet another conditionof aiming.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

Turning now to the drawings in greater particularity, and first to FIG.1, there will be seen a portion of the human body 10 illustratedsomewhat schematically. The body includes a kidney stone 12. It will beunderstood that the present invention could be utilized equally well toremove bladder stones, but the removal of kidney stones is a moreserious matter, and will be spoken of throughout.

An ellipsoidal reflector 14 is provided across its open end with adiaphragm 16 of elastomeric or plastic resin material, and is positionedagainst the body. The reflector is provided with a water inlet 18 havinga valve 20 through which the reflector is filled with water. A pair ofelectrodes 22 define a spark gap 24 at the first focal point of theellipsoid. A pulse generator 26 including a large capacitor and avoltage source is connected by means such as wires 28 to the electrodes22.

A sonar device 30 is provided, and is powered by suitable means, notshown. The sonar device is connected to a suitable transmitting andreceiving element 32 positioned in front of a reflector 34. The sonardevice 30 also is connected to a cathode ray tube display 36, havinghorizontal and vertical lines 38 and 40 displayed thereon. The sonardevice is operated, and the returning wave is compared with the timingof the output wave and controls positioning of the horizontal andvertical lines to indicate the position of the kidney stone 12. There isa further horizontal line 42 having a box 44 thereon. A blip or pip 46appears on the horizontal line 42 depending on the distance to thekidney stone 12 and the reflector 14, and hence the sonar transceiver 32is moved relative to the body to cause the blip 46 to move within thebox 44. This is in accordance with known sonar techniques. It will beappreciated that the human body exhibits considerable resilience,whereby the reflector 14 can be advanced or retracted relative to thebody to a minor degree. For major position changes a bellows mechanism(not shown) or other extensible devices can be incorporated into theopen end of the reflector.

The sonar reflector 34 may have a conical shield 48 behind it to preventengagement by rays of the shock waved generated by the spark gap 24.

Once the reflector 14 has been properly positioned relative to thekidney stone by use of the sonar device 30 and CRT display 36 the pulsegenerator 26 is started in operation. This produces a series of sparksacross the gap 24. Each spark causes immediate vaporization of watercreating a small cavitation bubble and creating a hydraulic shock wave.The shock waves are focused by the ellipsoidal reflector and converge onthe second focal point, namely the kidney stone 12. The size, thematerial of the kidney stone, and the manner in which it is securedtogether determine how much shock energy must be applied to the kidneystone to fragment it. One can estimate from a series of kidney stonedisintegrations approximately how much energy is needed for a stone of agiven size as shown on an X-ray. The composition cannot always bedetermined prior to the procedure.

When an amount of energy thought to be necessary to disintegrate thekidney stone has been delivered, then the procedure is stopped, andX-rays are taken to see if the kidney stone has been completelydestroyed.

The shock wave generated has a wave shape generally similar to theelectrical discharge wave of the capacitor in the pulse generator, andis shown at 50 in FIG. 2. The wave has a steep rise at 52, and acurving, slower descent 54, which may be shaped into one or more peaks56 caused by the changing of the spark gap upon sparking and the conicalshield 48.

The sonar device transmitting and receiving element 32 has been shown inthe ideal situation as being quite small. However, for an imaging typereadout it is necessary to provide both a non-focused transducer and afocused transducer. This structure is illustrated schematically in FIG.3 in which the focused transducer is illustrated at 60 and thenon-focused transducer is illustrated at 62. The focused transducer 60sends and receives a focused ultrasonic beam 64 to and from the kidneystone 12. The focused transducer is generally used for locating thedirection of the stone. The non-focused transducer 62 sends anon-focused ultrasonic wave 66 rearwardly against the reflector 34a(similar parts in FIG. 3 being identified by similar numerals with theaddition of the suffix a) from whence it is reflected at 68 to engagethe kidney stone 12 and to reflect back to the reflector 34a and to thenon-focused transducer. The non-focused transducer is used fordetermining the distance to the target.

For simplicity of illustration in FIG. 3 supports for the transducersand for the reflector and conical shield, and the water inlet have beenomitted. The same is true also in FIGS. 4-7.

The non-focused transducer is relatively small, and under mostcircumstances can be placed in the reflector. However, the focusedtransducer is larger, and in some cases it may get in the way of thewaves from the non-focused transducer, or it may get in the way of thehydraulic shock wave. To accommodate to this condition a modification ofthe invention is provided as shown in FIGS. 4 and 5, wherein similarparts are identified by the use of similar numerals with the addition ofthe suffix b. In this case, the focused transducer 60b is disposedexternally of the reflector 14b, and it is connected by a rigid supportmember 70 to a pivot 72. The reflector 14b is also connected by a rigidsupport member 74 to the pivot 72. In the specific example the axes ofthe reflector 14b and of the focused transducer 60b are disposed atright angles. The pivot member 72 is of the locking type, and the partsmay be positioned as in FIG. 4 with the reflector 14b in position foruse of the non-focused transducer 62b or for use in the hydraulic shockwave, or the parts may be pivoted 90 degrees to the position shown inFIG. 5 for use of the focused transducer 60b. The lengths of the supportmembers 70 and 74 are correlated so as to maintain the focusedtransducer 60b and the reflector 14b, and particularly the focal pointof the spark gap electrodes 22b in proper correlation relative to thekidney stone 12. It will be understood that the pivot member 72 isitself pivotally supported, or comprises a swivel, for pivoting movementperpendicular to the plane of the drawing to accommodate for the thirddimension necessary to aim at the kidney stone. This latter pivotalswivel may be omitted with other provision made for relative lateralpositioning of the reflector 14b and of the kidney stone 12. This may bedone by physically shifting the reflector 12b, or by shifting the bodybearing the kidney stone 12.

In still other instances it may be desired to position a non-focusedtransducer outside of the reflector. Such a modification is shown inFIGS. 6 and 7 wherein like parts are identified by similar numerals withthe addition of the suffix c. In this embodiment the focused transducer60c is again positioned at right angles to the reflector 14c, theseparts respectively being supported on support elements 70c and 74c fromthe pivot 72c. In this instance the non-focused transducer 62c issupported by support means such as a plurality of wires or rods (notshown) from the reflector 34c, which is in turn supported by supportmember 76 from the pivot member 72c. Although both transducers areillustrated as being supported at 90 degrees relative to the reflector14c, it is apparent that other angles could be used. The pivot member72c is pivotable 90 degrees in one direction to bring the focusedtransducer 60c into position for operation with the kidney stone 12,just as in FIG. 5, and the pivot 72c may be pivoted in the oppositedirection as shown in FIG. 7 to bring the non-focused transducer 62cinto position for operation with the kidney stone 12.

As noted earlier a CRT (cathode ray tube) display may utilize crosslines and align cross lines from the target kidney stone with base lineson the CRT. This is a known technique, and in most cases is expected tobe satisfactory. However, there is an ultrasonic imaging technique whichmay be preferred over the cross lines in many instances. Such imaging isillustrated in FIG. 8, in which the CRT display includes a box 78, theposition of which is controlled on the screen by the operator. The imagearea of interest contained by the box is then expanded to fill the fullscreen as in FIG. 9. Simultaneously, cross hairs 82 are generated in thecenter of the screen, and the focusing transducer is further oriented tomove the image 80 of the stone into position centered on the crosshairs.

The upper and lower portions of the screen then are blanked out to leaveonly an active center portion 82, and the non-focused transducer then isbrought into play to produce an image 80 of the kidney stone which ismoved by positioning the non-focused transducer into a position ofalignment with the cross hairs 82 which is used to determine theposition of the target kidney stone. When the image of the kidney stoneis centered on the cross hairs, then the non-focused transducer is atthe proper location from the kidney stone so that the reflector 14c canbe pivoted into position to have the spark gap 24c and the kidney stonelie on the two focus points of the elipsoidal reflector.

In each embodiment of the present invention the critical factor is thatthe ultrasonic aiming means is physically interconnected with theelipsoidal reflector so that the reflector can be positioned relative tothe body to place the kidney stone at one focus point of the elipsoid,the spark gap creating the hydraulic shock wave being at the other focuspoint. This can be effected by having an ultrasonic transducer withinthe elipsoidal reflector and movable with the reflector, or it can beeffected by having one or more ultrasonic transducers outside of thereflector, and one or none within the reflector, but bearingpredetermined relation to the reflector so that the reflector isultimately positioned in accordance with the positioning of theultrasonic transducer(s).

The specific examples of the invention as herein shown and described arefor illustrative purposes only. Various changes in structure will nodoubt occur to those skilled in the art, and will be understood asforming a part of the present invention insofar as they fall within thespirit and scope of the appended claims.

The invention is claimed as follows:
 1. Apparatus for the non-invasivedisintegration of concretions such as kidney stones within a livingbody, comprising means including a focussing reflector comprising aportion of an ellipsoid open at one end and having a first focus pointwithin said reflector and having a second focus point outside of saidreflector positioned beyond said open end, said first and second focuspoints lying on the focal axis of said reflector, said reflector beingadapted to contain a fluid such as water, a fluid retaining diaphragmclosing said open end and engagable with said body, sonic aiming meansdisposed entirely exteriorly of said reflector and positioned relativeto said reflector to permit said sonic aiming means to focus on saidconcretion exteriorly of and free of obstruction by said reflector, saidsonic aiming means having a focussing direction displaced from andnon-intersecting with said reflector focal axis, said reflector beinginterconnected with and movable with said sonic aiming means focus tobring said second focus point into coincidence with said concretion withconcurrent movement of said sonic aiming means away from saidconcretion, and spark gap means in said reflector at said first focuspoint for generating a shock wave which will travel through said fluid,said diaphram and through said body to disintegrate said concretion. 2.Apparatus as set forth in claim 1 wherein said sonic aiming means isphysically connected to said reflector.
 3. Apparatus as set forth inclaim 2 wherein said sonic aiming means is fixed relative to saidreflector.
 4. Apparatus as set forth in claim 3 and further includingmeans pivotally mounting said reflector.
 5. Apparatus as set forth inclaim 3 wherein said reflector has a major axis, and wherein said sonicaiming means is disposed at a predetermined angle relative to said majoraxis.
 6. Apparatus as set forth in claim 5 wherein said sonic aimingmeans comprises a focused sonic transducer and a non-focused sonictransducer.
 7. Apparatus as set forth in claim 6 wherein said focusedsonic transducer and said non-focused sonic transducer respectively lieon opposite sides of said reflector's major axis.
 8. Apparatus as setforth in claim 7 and further including means pivotally mounting saidreflector, said focused sonic transducer and said non-focused sonictransducer being aligned with one another and aimed in oppositedirections away from one another.
 9. Apparatus as set forth in claim 3wherein said sonic aiming means comprises a focused sonic transducer anda non-focused sonic transducer.
 10. Apparatus as set forth in claim 9wherein said focused sonic transducer and said non-focused sonictransducer are respectively located at two different positions.